SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aea67e0ccfba53581f0b553f24cb915e166d9a7e378ab455c5df567a05989e8e' 
  AND token = 'FMDK4Rnv42bUH56tAtCPKaJQiqFG2V4Rt2rXCpAxdG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}